Freezing of samples of e.g. biological material while maintaining the vitality of the sample material at temperatures of liquid nitrogen, i.e. −196° Celsius, is widely known in the areas of biology, pharmacology, medicine and biotechnology. Samples to be frozen and being designated as cryosamples are customarily stored and transferred in sample containers. Such sample containers, also denoted as cryotanks are typically filled with liquid nitrogen. Furthermore, such containers are thermally insulated and may resemble or comprise a so called Dewar vessel.
Insertion and extraction or removal of samples into and from such containers is sometimes critical. Especially when removing or extracting a sample from a filled sample container, a non-negligible amount of nitrogen may be spilled or may otherwise leave the container in a rather uncontrolled way. It is not only, that the cooling agent is spilled or wasted but that the surrounding air becomes enriched with gaseous nitrogen. Hence, there may further evolve a certain risk of health or of suffocating.
Document US 2006/0156753 A1 relates to the aspect of preventing a contact of the surrounding and relatively moist air when handling samples and/or sample containers. There, prevention of ice formation on the sample containers and/or samples and their germination is prevented in various ways. It is suggested to provide a protective container that receives the sample and/or the entire sample container during the handling. Moreover, a climate control equipment is provided which is connected to the protective container in order to dry and cool the ambient gas present in the protective container and/or replace it with the protective gas. Hence, an artificial atmosphere is preferably created in the protective container to prevent ice formation on the sample and/or sample container.
Complexity of the technical equipment to provide such a protective atmosphere is rather high as well as cost intensive.
It is therefore an object of the present invention to provide an improved cryopreservation device together with a recovery assembly for reducing and preventing uncontrolled escapement of the cooling agent. Moreover, consumption and waste of the cooling agent should be kept on a low or at least moderate level. It is a further aim to enhance operational safety of such devices and to protect operative staff against uncontrolled and vast exposure to the cooling agent, e.g. liquid nitrogen.